Background: Possible risk of cancer associated with use of cellular telephones has lately been a subject of public debate.
Methods: We conducted a register-based, case-control study on cellular phone use and cancer. The study subjects were all cases of brain tumor (N = 398) and salivary gland cancer (N = 34) diagnosed in Finland in 1996, with five controls per case.
Results: Cellular phone use was not associated with brain tumors or salivary gland cancers overall, but there was a weak association between gliomas and analog cellular phones.
Conclusions: A register-based approach has limited value in risk assessment of cellular phone use owing to lack of information on exposure.